[Soekris] Problem reading the serial port
soekris at laufquen.com.ar
Fri Nov 29 18:21:00 UTC 2002
Thank for your fast answer.
Yes, this is the problem, the 1-Wire interface take power from de serial.
I have 3 possible solutions:
>> Older boards can be modified by cutting the thin trace from U5 (MAX3243)
>> pin 23 to the capacitor next to it, and instead connecting pin 23 to pin
>> 22 with a solder bridge.
Mmmm... it's really small, I am afraid to break something.
Is the capacitor C49?
>> The net45xx series manufactured until about 2 months ago had the RS232
>> transceiver configured in a auto power saving mode where it turned ...
Do you know if is it possible to disable this mode from software?
I can power the sensors with 3V to 5V, taking about 15mA.
Can I take this power from the 4521?
Thank you again.
>> -----Original Message-----
>> From: Soren Kristensen [mailto:soren at soekris.com]
>> Posted At: Friday, November 29, 2002 5:14
>> Posted To: Soekris
>> Conversation: [Soekris] Problem reading the serial port
>> Subject: Re: [Soekris] Problem reading the serial port
>> Hi Pablo,
>> Pablo Berra wrote:
>> > Hi (sorry about my English),
>> > I want to implement a system using the DS1820 temperature
>> sensors from
>> > Dallas Semiconductors. This chip use the 1-Wire interface
>> connected at
>> > serial port (/dev/ttyS0).
>> > I am using the Net4521 with Linux (2.4.19) and digitemp (V
>> 1.6 for passive
>> > adapter) for reading the temperature and it gave me the
>> following error:
>> > digitemp -s/dev/ttyS0 -i
>> > Error initalizing OneWire device
>> > Error Searching for ROMs
>> > I turned off in initab and lilo config file the serial
>> references... so the
>> > /dev/ttyS0 is completly free..
>> > also i tried to set the ConLock value (set
>> conlock=disable) in the bios with
>> > error (dont know if this could help...)!!
>> > I try the same linux and digitemp version on another
>> machine... and it works
>> > perfectly....
>> > Any clues?
>> > Thanks in advance.
>> The net45xx series manufactured until about 2 months ago had
>> the RS232
>> transceiver configured in a auto power saving mode where it turned
>> itself off if there isn't any active inputs. That mean that devices
>> powered from the serial port doesn't work.... Is that the
>> case with your
>> application ?
>> Older boards can be modified by cutting the thin trace from
>> U5 (MAX3243)
>> pin 23 to the capacitor next to it, and instead connecting
>> pin 23 to pin
>> 22 with a solder bridge.
>> The updated boards are net4521 dated 020922, net4511 dated
>> 020922 and
>> net4501 dated 020910.
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